First of all, don’t panic! Most important for your son is to have as his mother-tongue Greek, which means that you speak to him in Greek as much as you can. Modern Greek is essentially the same with ancient Greek, so don't force your son to learn ancient Greek. When he grows, he will decide if he will learn or not, unless you see that he likes to learn even from now. Besides of speaking to him in Greek, go together with him (as much as he likes to go, don't force him) to the local Orthodox Church, participate in the Liturgy, speak to him about the Christ. Have in his room a byzantine icon of the Christ (by all means avoid protestant or catholic icons, which are just works of art, good or bad, but not revelations of Him).
To learn or remember your Homer, try Pharr's Homeric Greek
To find online editions of classical and byzantine texts, go to Elpenor's Resources